The field of the invention is control systems, and particularly, systems for controlling the motion of rotary veneer lathes.
Rotary veneer lathes are used for the production of green veneer from wood logs. They include a charger mechanism which positions a log between a spindle and a tailpiece and a spindle drive which rotates the log at high speed. A knife which extends the length of the log is fed into engagement with the rotating log to first round the log and then to peel a continuous web, or veneer, which is discharged onto an adjacent tray mechanism. The knife is advanced until the log reaches a specified minimum diameter, at which point the knife is withdrawn and another log is loaded into position by the charger mechanism.
Prior systems for controlling rotary veneer lathes feed the knife into the log at a rate which is determined by the rotary speed of the log and the desired thickness of the veneer. Manual controls enable the operator to retract the knife momentarily when the log is fully rounded and good veneer starts to be produced so that the scrap pieces can be removed from the tray before good veneer is produced in quantity. Also, such a momentary manual retract is required when large logs are being cut and the tray mechanism is filled to capacity. In either case, when cutting is resumed the knife is merely fed into the log again at the feedrate required to provide the desired veneer thickness.